| abstract |
This invention is an improved process for producing polyester copolymers, which employs a combination of an acid-based process and an ester-based process. The ester-based process is used to manufacture a low molecular weight naphthalate-based polymer, and the acid-based process is used to manufacture phthalate-based oligomers. The low molecular weight naphthalate-based polymer is combined with the phthalate-based oligomers, or the raw materials used to form the phthalate-based oligomers, to form a random polyester copolymer. Specifically, the process of the invention may be employed to manufacture, in an ester-based process, a low molecular weight polyethylene naphthalate polymer, which is then combined with polyethylene terephthalate oligomers produced in an acid-based process, and the acid-based process is then used to continue the polymerization reaction. Ester interchange reactions and further polymerization result in the production of a random polyethylene terephthalate/naphthalate copolymer. |